The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Hee Young Kwon - One of the best experts on this subject based on the ideXlab platform.
-
regulation of sirt1 ampk axis is critically involved in Gallotannin induced senescence and impaired autophagy leading to cell death in hepatocellular carcinoma cells
Archives of Toxicology, 2018Co-Authors: Hee Young Kwon, Sanjay K SrivastavaAbstract:Hepatocellular carcinoma (HCC) is one of the most fatal malignancies with high mortality worldwide. Here the underlying antitumor mechanism of Gallotannin was elucidated in HCC cells. Gallotannin suppressed viability and colony formation, increased subG1 portion and also induced senescence via upregulation of p21, G0/G1 arrest and higher SA-β-gal activity in HepG2 and SK-Hep1 cells. However, pan-caspase inhibitor Z-VAD-FMK reversed the ability of Gallotannin to activate caspase 3 at 48 h after treatment in two HCC cells. Of note, Gallotannin also induced autophagic features by increasing LC3 punctae, LC3B-II conversion, autophagic vacuoles and decreasing the expression of Beclin1 in two HCC cells. Furthermore, autophagy flux assay using GFP–mRFP–LC3 plasmid revealed increased yellowish color and late autophagy inhibitor CQ or NH4Cl enhanced cytotoxicity, LC3B-II conversion, and LC3 punctae in Gallotannin-treated HepG2 and SK-Hep1 cells compared to early autophagy inhibitor 3-MA or wortmannin. Interestingly, Gallotannin attenuated the expression of SIRT1 and mTOR and activated phosphorylation of AMPK in two HCC cells. Furthermore, AMPK activator AICAR significantly enhanced SA-β-gal activity and antiproliferation induced by Gallotannin, while AMPK inhibitor compound C did not in two HCC cells. Consistently, LC3B-II conversion by Gallotannin was not shown in AMPKα1 −/− MEF cells compared to WT AMPK +/+ MEF cells. Consistently, Gallotannin reduced in vivo growth of HepG2 cells implanted in NCr nude mice along with decreased expression of PCNA and SIRT1 and increased AMPKα1 and TUNEL. Overall, these findings highlight evidence that regulation of SIRT1/AMPK is critically involved in Gallotannin-induced senescence and impaired autophagy leading to cell death in HCC cells.
-
Regulation of SIRT1/AMPK axis is critically involved in Gallotannin-induced senescence and impaired autophagy leading to cell death in hepatocellular carcinoma cells
Archives of Toxicology, 2017Co-Authors: Hee Young Kwon, Sanjay K SrivastavaAbstract:Hepatocellular carcinoma (HCC) is one of the most fatal malignancies with high mortality worldwide. Here the underlying antitumor mechanism of Gallotannin was elucidated in HCC cells. Gallotannin suppressed viability and colony formation, increased subG1 portion and also induced senescence via upregulation of p21, G0/G1 arrest and higher SA-β-gal activity in HepG2 and SK-Hep1 cells. However, pan-caspase inhibitor Z-VAD-FMK reversed the ability of Gallotannin to activate caspase 3 at 48 h after treatment in two HCC cells. Of note, Gallotannin also induced autophagic features by increasing LC3 punctae, LC3B-II conversion, autophagic vacuoles and decreasing the expression of Beclin1 in two HCC cells. Furthermore, autophagy flux assay using GFP–mRFP–LC3 plasmid revealed increased yellowish color and late autophagy inhibitor CQ or NH4Cl enhanced cytotoxicity, LC3B-II conversion, and LC3 punctae in Gallotannin-treated HepG2 and SK-Hep1 cells compared to early autophagy inhibitor 3-MA or wortmannin. Interestingly, Gallotannin attenuated the expression of SIRT1 and mTOR and activated phosphorylation of AMPK in two HCC cells. Furthermore, AMPK activator AICAR significantly enhanced SA-β-gal activity and antiproliferation induced by Gallotannin, while AMPK inhibitor compound C did not in two HCC cells. Consistently, LC3B-II conversion by Gallotannin was not shown in AMPKα1 −/− MEF cells compared to WT AMPK +/+ MEF cells. Consistently, Gallotannin reduced in vivo growth of HepG2 cells implanted in NCr nude mice along with decreased expression of PCNA and SIRT1 and increased AMPKα1 and TUNEL. Overall, these findings highlight evidence that regulation of SIRT1/AMPK is critically involved in Gallotannin-induced senescence and impaired autophagy leading to cell death in HCC cells.
-
abstract 3545 Gallotannin induces senescence and autophagy leading to cell death via sirt1 inhibition and ampk activation in hepatocellular carcinoma cells
Cancer Research, 2016Co-Authors: Hee Young KwonAbstract:Hepatocellular carcinoma (HCC) is one of the most fatal malignancies with high mortality rate worldwide. In the present study, the underlying antitumor mechanism of Gallotannin, a hydrolysable tannic acid, was elucidated in HepG2 and SKHep1 HCC cells. Gallotannin suppressed growth and colony formation and also induced senescence via upregulation of p21, G0 / G1 arrest and higher senescence-associated β-galactosidase (SA-β-gal) activity within 24 h culture in HepG2 and SKHep1 cells. Of note, Gallotannin also induced autophagy by increasing the number of protein-cytosol-associated protein light chain 3 (LC3) punctae, LC3B-II conversion and SQSTM1/p62, autophagic vacuoles (AVOs) by transmission electron microscopy (TEM) and decreasing the of Beclin1 in HepG2 and SKHep1 cells. A tandem fluorescent-tagged LC3 reporter plasmid (GFP-mRFP-LC3) transfection revealed that Gallotannin increased the number of yellow colored LC3 punctae through the co-localization of GFP and mRFP punctae and yellow colored LC3 punctae were increased by CQ or NH4Cl with accumulation of autophagosomes, LC3B-II and SQSTM1/p62 in HepG2 and SKHep1 cells. Additionally, Gallotannin attenuated the of sirtuin1 (SIRT1) and mTOR and activated the phosphorylation of 5′-AMP activated protein kinase (AMPK) in two HCC cells. Furthermore, AMPK activator AICAR significantly enhanced SA-β-gal activity and antiproliferation induced by Gallotannin, while AMPK inhibitor compound C did not in two HCC cells. Of note, Gallotannin time dependently activated caspase 8 / 3 and time/concentration dependently increased sub G1 portion along with weak cleavages of PARP in two HCC cells. Collectively, Gallotannin induces senescence and inhibits late autophagy flux, finally leading to apoptotic cell death in HepG2 and SKHep1 cells via inhibition of SIRT1 and activation of p-AMPK as a potent antitumor agent for HCC treatment. Citation Format: Hee Young Kwon, Sung-hoon Kim. Gallotannin induces senescence and autophagy leading to cell death via SIRT1 inhibition and AMPK activation in hepatocellular carcinoma cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3545.
-
inhibition of myeloid cell leukemia 1 and activation of caspases are critically involved in Gallotannin induced apoptosis in prostate cancer cells
Phytotherapy Research, 2015Co-Authors: Eunkyung Park, Hee Young Kwon, Ji Hoon Jung, Deokbeom Jung, Arong Jeong, Jinhong CheonAbstract:Although Gallotannin contained in several medicinal plants was known to have multi-biological activities, such as antioxidant, antiinflammatory, antimicrobial, immunomodulatory, and antitumor effects, the underlying apoptotic mechanism of Gallotannin is not fully understood so far. Thus, in the present study, the apoptotic mechanism of Gallotannin was elucidated in DU145, PC-3, and M2182 prostate cancer cells in association with myeloid cell leukemia 1 (Mcl-1) signaling. Gallotannin exerted dose-dependent cytotoxicity in DU145, PC-3, and M2182 prostate cancer cells. Also, Gallotannin showed apoptotic morphological features and increased the number of terminal deoxynucleotidyl transferase dUTP nick end labeling positive cells and sub-G1 accumulation in three prostate cancer cell lines. Consistently, Gallotannin cleaved poly (ADP-ribose) polymerase (PARP) and attenuated the expression of procaspases 9 and 3 in three prostate cancer cell lines. Furthermore, Gallotannin attenuated the expression of survival genes such as Mcl-1, B-cell lymphoma 2, and B-cell lymphoma 2 extra large in three prostate cancer cell lines. Interestingly, overexpression of Mcl-1 reversed the ability of Gallotannin to cleave PARP and increase sub-G1 population in three prostate cancer cell lines. Conversely, silencing of Mcl-1 enhanced apoptosis by Gallotannin in three prostate cancer cell lines by FACSCalibur (Becton Dickinson, Franklin Lakes, NJ, USA). Taken together, our findings demonstrate that inhibition of Mcl-1 and activation of caspases are critically involved in Gallotannin-induced apoptosis in prostate cancer cells. Copyright © 2015 John Wiley & Sons, Ltd.
-
abstract 26 suppression of e cadherin mediates Gallotannin induced apoptosis in hep g2 hepatocelluar carcinoma cells
Cancer Research, 2015Co-Authors: Hee Young Kwon, Ji Hoon Jung, Myoung Seok Jeong, Deokbeom JungAbstract:Though Gallotannin was known to have anti-oxidant and antitumor activity, the underlying antitumor mechanism of Gallotannin still remains unclear. Thus, in the present study, antitumor mechanism of Gallotannin was elucidated in hepatocellular carcinoma cells. Gallotannin significantly exerted cytotoxicity against Hep G2 and Chang hepatocellular carcinoma cells with the accumulation of the sub-G1 population and increase of terminal deoxynucleotidyltransferasedUTP nick end labeling (TUNEL) positive cells as an apoptotic feature. Also, Gallotannin attenuated the expression of pro-caspase9, pro-caspase3, Bcl2 and integrin β1 and cleaved poly(ADP)-ribose polymerase (PARP) in Hep G2 and Chang cancer cells. Furthermore, Gallotannin suppressed cell repair motility by wound healing assay and also inhibited cell adhesion in Hep G2 cells. Of note, Gallotannin attenuated the expression of epithelial cadherin (E-cadherin) to form cell-cell adhesion from the early stage, and also beta-catenin at late phase in Hep G2 cells. Consistently, Immunofluorescence assay showed that E-cadherin or β-catenin expression was suppressed in a time dependent manner by Gallotannin. Furthermore, silencing of E-cadherin by siRNA transfection method enhanced PAPR cleavage, caspase 3 activation and sub G1 population and attenuated the cell adhesion induced by Gallotannin in Hep G2 cells. Overall, our findings demonstrate that the disruption of cell adhesion junction by suppression of E-cadherin mediates Gallotannin enhanced apoptosis in Hep G2 liver cancer cells. Citation Format: Hee Young Kwon, Ji Hoon Jung, Hyun Joo Lee, Myoung Seok Jeong, Deok-Beom Jung, Bonglee Kim, Hyemin Lee, Sung-Hoon Kim. Suppression of E-cadherin mediates Gallotannin-induced apoptosis in Hep G2 hepatocelluar carcinoma cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 26. doi:10.1158/1538-7445.AM2015-26
Georg G Gross - One of the best experts on this subject based on the ideXlab platform.
-
enzymology of Gallotannin and ellagitannin biosynthesis
Phytochemistry, 2005Co-Authors: Ruth Niemetz, Georg G GrossAbstract:Abstract Gallotannins and ellagitannins, the two subclasses of hydrolyzable tannins, are derivatives of 1,2,3,4,6-penta- O -galloyl-β- d -glucopyranose. Enzyme studies with extracts from oak leaves ( Quercus robur , syn. Quercus pedunculata; Quercus rubra ) and from staghorn sumac ( Rhus typhina ) revealed that this pivotal intermediate is synthesized from β-glucogallin (1- O -galloyl-β- d -glucopyranose) by a series of strictly position-specific galloylation steps, affording so-called ‘simple’ Gallotannins, i.e., mono- to pentagallyoylglucose esters. Besides its role as starter molecule, β-glucogallin was also recognized as the principal energy-rich acyl donor required in these transformations. Subsequent pathways to ‘complex’ Gallotannins have recently been elucidated by the isolation of five different enzymes from sumac leaves that were purified to apparent homogeneity. They catalyzed the β-glucogallin-dependent galloylation of pentagallyoylglucose to a variety of hexa- and heptagalloylglucoses, plus several not yet characterized higher substituted analogous galloylglucoses. With respect to the biosynthesis of ellagitannins, postulates that had been formulated already decades ago were proven by the purification of a new laccase-like phenol oxidase from leaves of fringe cups ( Tellima grandiflora ) that regio- and stereospecifically oxidized pentagallyoylglucose to the monomeric ellagitannin, tellimagrandin II. This compound was further oxidized by a similar but different laccase-like oxidase to yield a dimeric ellagitannin, cornusiin E.
-
Gallotannin biosynthesis two new galloyltransferases from rhus typhina leaves preferentially acylating hexa and heptagalloylglucoses
Planta, 2002Co-Authors: Brigitte Frohlich, Ruth Niemetz, Georg G GrossAbstract:Current enzyme studies on the biosynthesis of Gallotannins with cell-free extracts from leaves of staghorn sumac (Rhus typhina L.) revealed the existence of two new β-glucogallin-dependent galloyltransferases (EC 2.3.1.-) that preferentially catalyzed the acylation of hexa- and heptagalloylglucoses. One enzyme was most active with the hexagalloylglucose, 3-O-digalloyl-1,2,4,6-tetra-O-galloylglucose, to form the corresponding heptagalloylglucose, 3-O-trigalloyl-1,2,4,6-tetra-O-galloylglucose. This polyester, in turn, was the preferred substrate for a second enzyme that catalyzed its conversion to higher substituted derivatives. This latter enzyme also displayed considerable affinity towards 2-O-digalloyl-1,3,4,6-tetra-O-galloylglucose which was acylated to various hepta- and octagalloylglucoses. These recent findings, together with data from earlier reported related enzymes, allowed the presentation of a scheme that summarizes the major transitions in the biogenetic routes from 1,2,3,4,6-pentagalloylglucose to complex Gallotannins.
-
Gallotannin biosynthesis a new β glucogallin dependent galloyltransferase from sumac leaves acylating Gallotannins at positions 2 and 4
Journal of Plant Physiology, 1999Co-Authors: Ruth Niemetz, Georg G GrossAbstract:Summary Leaves of Saghorn sumac ( Rhus typhina ) contain. several isoenzymes that catalyze the R-glucogallin (1- O -galloyl-β-D-glucose)-dependent transformation of 1,2,3,4,6-penta- O -galloyl-β-D-glucose to complex Gallotannins. Among these, a new galloyltransferase has been isolated that preferentially acylated the 4-position of the substrate, followed by substitution of the 2-position, thus yielding the hexa-galloylglucose, 4- O -digalloyl-1,2,3,6-tetra- O -galloyl-β-D-glucose, and the heptagalloylglucose, 2,4-di- O -digalloyl-1,3,6-tri- O -galloyl-β-D-glucose. The enzyme, for which a M r value of 360,000 was determined by gel filtration, was purified more than 500-fold to apparent homogeneity and was most reactive with hexagalloylglucose as acceptor substrate. The transferase had a pH optimum at 4.8, an isoelectric point at pH 4.95, was stable between pH 3.7 and 6.8, and proved comparatively heat-stable as shown by a temperature optimum of 40 °C and a half-maximal activity at 64 °C.
-
Gallotannin biosynthesis purification of β glucogallin 1 2 3 4 6 pentagalloyl β d glucose galloyltransferase from sumac leaves
Phytochemistry, 1998Co-Authors: Ruth Niemetz, Georg G GrossAbstract:An enzyme from leaves of staghorn sumac (Rhus typhina) that catalysed the galloylation of 1,2,3,4,6-penta-O-galloyl-β-d-glucose to the Gallotannin, 3-O-digalloyl-1,2,4,6-tetra-O-galloyl-β-d-glucose, was purified more than 500-fold to apparent homogeneity. β-Glucogallin (1-O-galloyl-β-d-glucopyranose) served as activated acyl donor in this conversion. For the native enzyme, a Mr value of 170,000 was determined by gel filtration, while a single polypeptide band of Mr 42,000 was detected by SDS-PAGE. The acyltransferase had pH and temperature optima of 4–4.5 and 25°, respectively, and was most stable between pH 3 and 4.5. Besides the major substrate, pentagalloylglucose, also 1,2,3,6-tetragalloylglucose and hexa- to nona-substituted Gallotannins were accepted as minor substrates by this new enzyme for which the systematic name ‘‘β-glucogallin: 1,2,3,4,6-pentagalloyl-β-d-glucose (3-O-galloyl)-galloyltransferase’’ (EC 2.3.1.-) is proposed.
-
Biosynthesis of Gallotannins
Planta, 1991Co-Authors: Klaus Denzel, Georg G GrossAbstract:Cell-free extracts from leaves of Rhus typhina L. (sumach) were found to transfer the 1-O-galloyl moiety of l,6-di-O-galloyl-β-d-glucose to the 2-position of the same compound, yielding 1,2,6-tri-O-galloyl-β-d-glucose and leaving 6-O-galloylglucose as the deacylated by-product. The enzyme catalyzing this ‘disproportionation’ was purified almost 1700-fold. It had a molecular weight of approx. 56 000, a Km value of 11.5 mM, was stable between pH 4.5 and 6.5, and most active at pH 5.9 and 40° C. The systematic name “1,6-di-O-galloyl-glucose: 1,6-di-O-galloylglucose 2-O-galloyltransferase” (EC 2.3.1.) was proposed for this new enzyme whose detection provided evidence that, in addition to β-glucogallin (1-O-galloyl-β-d-glucose), higher substituted glucose esters also have the potential to serve as acyl donors in the biosynthesis of Gallotannins.
Ruth Niemetz - One of the best experts on this subject based on the ideXlab platform.
-
enzymology of Gallotannin and ellagitannin biosynthesis
Phytochemistry, 2005Co-Authors: Ruth Niemetz, Georg G GrossAbstract:Abstract Gallotannins and ellagitannins, the two subclasses of hydrolyzable tannins, are derivatives of 1,2,3,4,6-penta- O -galloyl-β- d -glucopyranose. Enzyme studies with extracts from oak leaves ( Quercus robur , syn. Quercus pedunculata; Quercus rubra ) and from staghorn sumac ( Rhus typhina ) revealed that this pivotal intermediate is synthesized from β-glucogallin (1- O -galloyl-β- d -glucopyranose) by a series of strictly position-specific galloylation steps, affording so-called ‘simple’ Gallotannins, i.e., mono- to pentagallyoylglucose esters. Besides its role as starter molecule, β-glucogallin was also recognized as the principal energy-rich acyl donor required in these transformations. Subsequent pathways to ‘complex’ Gallotannins have recently been elucidated by the isolation of five different enzymes from sumac leaves that were purified to apparent homogeneity. They catalyzed the β-glucogallin-dependent galloylation of pentagallyoylglucose to a variety of hexa- and heptagalloylglucoses, plus several not yet characterized higher substituted analogous galloylglucoses. With respect to the biosynthesis of ellagitannins, postulates that had been formulated already decades ago were proven by the purification of a new laccase-like phenol oxidase from leaves of fringe cups ( Tellima grandiflora ) that regio- and stereospecifically oxidized pentagallyoylglucose to the monomeric ellagitannin, tellimagrandin II. This compound was further oxidized by a similar but different laccase-like oxidase to yield a dimeric ellagitannin, cornusiin E.
-
Gallotannin biosynthesis two new galloyltransferases from rhus typhina leaves preferentially acylating hexa and heptagalloylglucoses
Planta, 2002Co-Authors: Brigitte Frohlich, Ruth Niemetz, Georg G GrossAbstract:Current enzyme studies on the biosynthesis of Gallotannins with cell-free extracts from leaves of staghorn sumac (Rhus typhina L.) revealed the existence of two new β-glucogallin-dependent galloyltransferases (EC 2.3.1.-) that preferentially catalyzed the acylation of hexa- and heptagalloylglucoses. One enzyme was most active with the hexagalloylglucose, 3-O-digalloyl-1,2,4,6-tetra-O-galloylglucose, to form the corresponding heptagalloylglucose, 3-O-trigalloyl-1,2,4,6-tetra-O-galloylglucose. This polyester, in turn, was the preferred substrate for a second enzyme that catalyzed its conversion to higher substituted derivatives. This latter enzyme also displayed considerable affinity towards 2-O-digalloyl-1,3,4,6-tetra-O-galloylglucose which was acylated to various hepta- and octagalloylglucoses. These recent findings, together with data from earlier reported related enzymes, allowed the presentation of a scheme that summarizes the major transitions in the biogenetic routes from 1,2,3,4,6-pentagalloylglucose to complex Gallotannins.
-
Gallotannin biosynthesis a new β glucogallin dependent galloyltransferase from sumac leaves acylating Gallotannins at positions 2 and 4
Journal of Plant Physiology, 1999Co-Authors: Ruth Niemetz, Georg G GrossAbstract:Summary Leaves of Saghorn sumac ( Rhus typhina ) contain. several isoenzymes that catalyze the R-glucogallin (1- O -galloyl-β-D-glucose)-dependent transformation of 1,2,3,4,6-penta- O -galloyl-β-D-glucose to complex Gallotannins. Among these, a new galloyltransferase has been isolated that preferentially acylated the 4-position of the substrate, followed by substitution of the 2-position, thus yielding the hexa-galloylglucose, 4- O -digalloyl-1,2,3,6-tetra- O -galloyl-β-D-glucose, and the heptagalloylglucose, 2,4-di- O -digalloyl-1,3,6-tri- O -galloyl-β-D-glucose. The enzyme, for which a M r value of 360,000 was determined by gel filtration, was purified more than 500-fold to apparent homogeneity and was most reactive with hexagalloylglucose as acceptor substrate. The transferase had a pH optimum at 4.8, an isoelectric point at pH 4.95, was stable between pH 3.7 and 6.8, and proved comparatively heat-stable as shown by a temperature optimum of 40 °C and a half-maximal activity at 64 °C.
-
Gallotannin biosynthesis purification of β glucogallin 1 2 3 4 6 pentagalloyl β d glucose galloyltransferase from sumac leaves
Phytochemistry, 1998Co-Authors: Ruth Niemetz, Georg G GrossAbstract:An enzyme from leaves of staghorn sumac (Rhus typhina) that catalysed the galloylation of 1,2,3,4,6-penta-O-galloyl-β-d-glucose to the Gallotannin, 3-O-digalloyl-1,2,4,6-tetra-O-galloyl-β-d-glucose, was purified more than 500-fold to apparent homogeneity. β-Glucogallin (1-O-galloyl-β-d-glucopyranose) served as activated acyl donor in this conversion. For the native enzyme, a Mr value of 170,000 was determined by gel filtration, while a single polypeptide band of Mr 42,000 was detected by SDS-PAGE. The acyltransferase had pH and temperature optima of 4–4.5 and 25°, respectively, and was most stable between pH 3 and 4.5. Besides the major substrate, pentagalloylglucose, also 1,2,3,6-tetragalloylglucose and hexa- to nona-substituted Gallotannins were accepted as minor substrates by this new enzyme for which the systematic name ‘‘β-glucogallin: 1,2,3,4,6-pentagalloyl-β-d-glucose (3-O-galloyl)-galloyltransferase’’ (EC 2.3.1.-) is proposed.
Deokbeom Jung - One of the best experts on this subject based on the ideXlab platform.
-
inhibition of myeloid cell leukemia 1 and activation of caspases are critically involved in Gallotannin induced apoptosis in prostate cancer cells
Phytotherapy Research, 2015Co-Authors: Eunkyung Park, Hee Young Kwon, Ji Hoon Jung, Deokbeom Jung, Arong Jeong, Jinhong CheonAbstract:Although Gallotannin contained in several medicinal plants was known to have multi-biological activities, such as antioxidant, antiinflammatory, antimicrobial, immunomodulatory, and antitumor effects, the underlying apoptotic mechanism of Gallotannin is not fully understood so far. Thus, in the present study, the apoptotic mechanism of Gallotannin was elucidated in DU145, PC-3, and M2182 prostate cancer cells in association with myeloid cell leukemia 1 (Mcl-1) signaling. Gallotannin exerted dose-dependent cytotoxicity in DU145, PC-3, and M2182 prostate cancer cells. Also, Gallotannin showed apoptotic morphological features and increased the number of terminal deoxynucleotidyl transferase dUTP nick end labeling positive cells and sub-G1 accumulation in three prostate cancer cell lines. Consistently, Gallotannin cleaved poly (ADP-ribose) polymerase (PARP) and attenuated the expression of procaspases 9 and 3 in three prostate cancer cell lines. Furthermore, Gallotannin attenuated the expression of survival genes such as Mcl-1, B-cell lymphoma 2, and B-cell lymphoma 2 extra large in three prostate cancer cell lines. Interestingly, overexpression of Mcl-1 reversed the ability of Gallotannin to cleave PARP and increase sub-G1 population in three prostate cancer cell lines. Conversely, silencing of Mcl-1 enhanced apoptosis by Gallotannin in three prostate cancer cell lines by FACSCalibur (Becton Dickinson, Franklin Lakes, NJ, USA). Taken together, our findings demonstrate that inhibition of Mcl-1 and activation of caspases are critically involved in Gallotannin-induced apoptosis in prostate cancer cells. Copyright © 2015 John Wiley & Sons, Ltd.
-
abstract 26 suppression of e cadherin mediates Gallotannin induced apoptosis in hep g2 hepatocelluar carcinoma cells
Cancer Research, 2015Co-Authors: Hee Young Kwon, Ji Hoon Jung, Myoung Seok Jeong, Deokbeom JungAbstract:Though Gallotannin was known to have anti-oxidant and antitumor activity, the underlying antitumor mechanism of Gallotannin still remains unclear. Thus, in the present study, antitumor mechanism of Gallotannin was elucidated in hepatocellular carcinoma cells. Gallotannin significantly exerted cytotoxicity against Hep G2 and Chang hepatocellular carcinoma cells with the accumulation of the sub-G1 population and increase of terminal deoxynucleotidyltransferasedUTP nick end labeling (TUNEL) positive cells as an apoptotic feature. Also, Gallotannin attenuated the expression of pro-caspase9, pro-caspase3, Bcl2 and integrin β1 and cleaved poly(ADP)-ribose polymerase (PARP) in Hep G2 and Chang cancer cells. Furthermore, Gallotannin suppressed cell repair motility by wound healing assay and also inhibited cell adhesion in Hep G2 cells. Of note, Gallotannin attenuated the expression of epithelial cadherin (E-cadherin) to form cell-cell adhesion from the early stage, and also beta-catenin at late phase in Hep G2 cells. Consistently, Immunofluorescence assay showed that E-cadherin or β-catenin expression was suppressed in a time dependent manner by Gallotannin. Furthermore, silencing of E-cadherin by siRNA transfection method enhanced PAPR cleavage, caspase 3 activation and sub G1 population and attenuated the cell adhesion induced by Gallotannin in Hep G2 cells. Overall, our findings demonstrate that the disruption of cell adhesion junction by suppression of E-cadherin mediates Gallotannin enhanced apoptosis in Hep G2 liver cancer cells. Citation Format: Hee Young Kwon, Ji Hoon Jung, Hyun Joo Lee, Myoung Seok Jeong, Deok-Beom Jung, Bonglee Kim, Hyemin Lee, Sung-Hoon Kim. Suppression of E-cadherin mediates Gallotannin-induced apoptosis in Hep G2 hepatocelluar carcinoma cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 26. doi:10.1158/1538-7445.AM2015-26
Rabi Ranjan Chattopadhyay - One of the best experts on this subject based on the ideXlab platform.
-
synergistic antibiofilm efficacy of a Gallotannin 1 2 6 tri o galloyl β d glucopyranose from terminalia chebula fruit in combination with gentamicin and trimethoprim against multidrug resistant uropathogenic escherichia coli biofilms
PLOS ONE, 2017Co-Authors: Rabi Ranjan ChattopadhyayAbstract:In recent years the emergence of multiple drug resistance microbes has become a global public health problem. The aim of the present investigation was to evaluate possible antibiofilm efficacy of a Gallotannin 1,2,6-tri-O-galloyl-β-D-glucopyranose from Terminalia chebula fruits alone and in combination with gentamicin and trimethoprim against preformed biofilms of multidrug-resistant (MDR) uropathogenic E. coli isolates using microbroth dilution, checkerboard titration and kill kinetics methods. Test Gallotannin showed > 50% antibiofilm efficacy after 24 h when administered alone whereas gentamicin and trimethoprim failed to do so. But in combination, test Gallotannin/gentamicin and test Gallotannin/trimethoprim showed 71.24±6.75% and 93.4±8.46% antibiofilm activity respectively. On the basis of FICI values, test Gallotannin/gentamicin showed synergistic interactions against 71.42% and test Gallotannin/trimethoprim against 85.71% biofilm forming test bacterial isolates. Kill-kinetics study confirmed their synergistic interactions. Thus, gentamicin and trimethoprim in combination with test Gallotannin may have potential for treatment of urinary tract infections caused by biofilm forming MDR uropathogenic E. coli.
-
efflux pump inhibitory activity of a Gallotannin from terminalia chebula fruit against multidrug resistant uropathogenic escherichia coli
Natural Product Research, 2014Co-Authors: Rabi Ranjan ChattopadhyayAbstract:This study was carried out to evaluate the possible efflux-pump inhibitory activity of a Gallotannin 1,2,6-tri-O-galloyl-β-d-glucopyranose isolated from Terminalia chebula fruit against multidrug-resistant (MDR) uropathogenic Escherichia coli. Susceptibility tests of antibiotics and ethidium bromide in the presence and absence of isolated Gallotannin and phenylalanine-arginine β-naphthylamide (PAβN) were conducted by using the microbroth dilution assay. Ethidium bromide accumulation and efflux assays were performed spectrofluorometrically to elucidate the possible resistance-modifying activity of isolated gallotanin, if any. Minimum inhibitory concentrations of test antibiotics and ethidium bromide were reduced in the presence of isolated Gallotannin and PAβN. The isolated Gallotannin also demonstrated efflux-pump inhibitory activity against the studied bacteria as evidenced from ethidium bromide accumulation and efflux assays. The isolated Gallotannin, 1,2,6-tri-O-galloyl-β-d-glucopyranose exhibited effl...
